Book Image

Docker Orchestration

By : Randall Smith
Book Image

Docker Orchestration

By: Randall Smith

Overview of this book

Docker orchestration is what you need when transitioning from deploying containers individually on a single host to deploying complex multi-container apps on many machines. This book covers the new orchestration features of Docker 1.12 and helps you efficiently build, test, and deploy your application using Docker. You will be shown how to build multi-container applications using Docker Compose. You will also be introduced to the building blocks for multi-host Docker clusters such as registry, overlay networks, and shared storage using practical examples. This book gives an overview of core tools such as Docker Machine, Swarm, and Compose which will enhance your orchestration skills. You’ll learn how to set up a swarm using the decentralized building block. Next, you’ll be shown how to make the most out of the in-built orchestration feature of Docker engine and you’ll use third-party tools such as Kubernetes, Mesosphere, and CoreOS to orchestrate your existing process. Finally, you will learn to deploy cluster hosts on cloud services and automate your infrastructure.
Table of Contents (17 chapters)
Docker Orchestration
About the Author
About the Reviewer
Customer Feedback

Managing services

Now that the swarm is up and running, it is time to look at services. A service is a collection of one or more tasks that do something. Each task is a container running somewhere in the swarm. Since services are potentially composed of multiple tasks, there are different tools to manage them. In most cases, these commands will be a subcommand of docker service.

Running containers as services in a swarm offers a number of benefits. They are as follows:

  • Services can be scaled out quickly and easily.

  • Swarm can perform zero-downtime upgrades where updated versions of an image are added while old versions are removed.

  • Easily create overlay networks to connect containers running on multiple hosts. (Overlay networks were covered in detail in Chapter 3, Cluster Building Blocks – Registry, Overlay Networks, and Shared Storage.)

Running services

Running tasks with Docker Swarm is a little bit different than running them under plain Docker. Instead of using docker run, the command is docker...